I'm not quite following why this is not relevant to the OP's question. I suppose I'm saying that it's not just a hard task, but an almost impossible one. Lots of people (2000 years ago, say) thought that what they were writing was of world-historical significance; today, we barely know their names. Others dashed off dictated letters to small, fragile communities of early followers and just happened to have created among the most well preserved texts of all time.
All I'm really saying here is that among the titanic forces determining which is which, the type of ink used seems not to be a matter of much importance.